Heat exchangers have been utilized successfully in a wide variety of diverse applications. Such applications range from the mundane heating and cooling requirements of the home to sophisticated applications of the types encountered in scientific experimentation, manufacturing processes, and the like. However, in most cases, it is important for a heat exchanger to operate in a controlled manner in order to be useful.
In some applications, the heat exchanger has utilized impingement spraying of a liquid coolant to maximize heat transfer while other applications channel a liquid coolant through baffles for this purpose. Nevertheless, in such applications, the heat exchanger has nearly always operated by transferring heat into a working fluid, and in some instances the working fluid was heated to the point of generating vapor or steam.
Among the heat transfer devices proposed is that disclosed in Peck U.S. Pat. No. 3,971,435. This device utilizes a series of longitudinal grooves running along the length of a base and covered by a plate having a plurality of openings registering with the grooves, and it operates such that the space outwardly of the plate serves as an evaporator region with the space between the plate and the grooves serving as a condensor region. When condensed, liquid is transported by capillary action in the grooves from the condensor region to the evaporator region of the device.
Another cooling arrangement is disclosed in IBM Technical Disclosure Bulletin, Vol. 20, No. 8 (January 1978). This is a diaphragm cooling arrangement for cooling semiconductor chips in which a coolant is sprayed against the underside of a diaphragm having contact areas for abutment with the back side of the chips which are flip-chip mounted on a ceramic substrate. With this arrangement, a jet of coolant can be directed against contact areas of the diaphragm under suitable pressure and then deflected downward into a pool of coolant.
Still another effort to provide a cooling system is disclosed in Wilson et al U.S. Pat. No. 4,109,707. This cooling system is for electronic systems and, in particular, for cooling large scale integrated circuit chips mounted on substates in which the heat exchanger has a flexible wall mounted in close proximity to a surface of the substrate to be cooled together with labyrinth passages to circulate coolant over the flexible wall to maximize heat exchange. In this manner, the uniform flow of the liquid coolant over the inner surface of the flexible wall is more closely assured.
In a particular application of interest, it is necessary to cool both lab modules and habitated modules in a space station. In this application, it is particularly desirable and an object of the invention to provide a steady state heat exchange system in which a liquid is cooled to cool, in turn, an adjacent environment in which, in the space station application, the liquid must be non-toxic and non-flammable such as water. In order to take heat out of each module, an interface contact heat exchanger can be utilized with a central thermal bus operating with ammonia at a temperature very near the freezing point of water.
With such arrangements, the design of the heat exchanger is most important because regulation of the temperature and pressure of the central thermal bus must be quite exact if localized freezing is to be avoided and damage from indefinite freeze and thaw cycles to the interface contact heat exchanger must be avoided if localized freezing is to be allowed. Additionally, the interface contact heat exchanger must not stop the flow of liquid coolant by freezing solid, should not release any ice particles interfering with return flow of liquid coolant, and must ensure the proper functioning of the cooling system's temperature control valve in spite of the freeze and thaw cycles.
The present invention is directed to overcoming the above stated problems and accomplishing the stated objects.